In modern radar electronic warfare, a variety of counter-measures are used by hostile or enemy targets to avoid detection and/or deny range information, the distance between the aircraft and the target. For example, a pilot of an enemy aircraft with an on-board or escort ECM system wishes to avoid being prey to a missile by denying range for missile launch envelope calculation by another radar. A typical radar ECM is the noise jammer which conventionally broadcasts random in-band electronic energy to overcome for a period of time the ability of a victim radar system to detect and obtain range measurements of, or range on, the target being protected by the noise. Methods have been devised to overcome this kind of jamming, as for example, the polarization canceller. Recently, rapidly blinking and polarization agile noise jamming ECM techniques have been developed. Blinking jamming results when the enemy jammer periodically broadcasts powerful noise energy to defeat conventional polarization canceller ECCM techniques with rapid blink rates, because as the radar system's receive polarization adjusts to the jamming noise, the noise disappears. In polarization agile noise, the enemy ECM system switches rapidly between different polarizations of antennas. Conventional Polarization canceller ECCM for noise jamming fails for this jamming technique as well, when it is too rapidly agile, because as the radar system becomes accustomed to one polarization, another polarization is transmitted by the hostile target.
Furthermore, conventional polarization ECCMs for noise jamming techniques do not operate well with multiple jammers in the antenna main lobe. Such techniques are configured to cancel only single jammers in the main lobe, and are ineffective against multiple jammers.
Consequently, it would be an advance in the art for radars to be able to and cancel the effects of multiple noise jammers in the main lobe order to range on and track enemy targets in range and doppler.